A Pakistani police officer pushes back people from the site of explosion in Peshawar, Pakistan, on April 29, 2013. / Mohammad Sajjad, AP

by USA TODAY

by USA TODAY

PESHAWAR, Pakistan (AP) - A suicide bomber targeting policemen killed six people in northwestern Pakistan on Monday in the latest attack ahead of next month's parliamentary election, police said.

The bomber, who was riding a motorcycle, detonated his explosives as a police patrol passed in the main northwestern city of Peshawar, said city police chief Liaqat Ali Khan.

Three policemen were among over 30 people who were wounded by the blast, Khan said. Many of the dead and wounded were from a nearby passenger bus, which bore the brunt of the attack.

Local TV footage showed the wreckage of the bus and the motorcycle, as rescue workers rushed wounded people to hospitals in the city.

No one immediately claimed responsibility, but suspicion will likely to fall on the Pakistani Taliban. The group has been waging a bloody insurgency against the government for years and has stepped up attacks ahead of the May 11 parliamentary election.

On Sunday, the Taliban killed 11 people in bomb attacks on a political rally and two campaign offices in the northwest, part of their quest to disrupt the election. The group has killed at least 60 people in attacks on politicians and party workers since the beginning of April.

The Taliban have specifically targeted more secular political parties that have supported military offensives against the militants in the northwest. The Taliban have largely spared Islamic parties and others who believe the government should strike a peace deal with the militants, rather than fight them.

There is a concern that the violence could benefit the parties that take a softer line toward the militants because they are able to campaign more freely.

"Unless the government, the country's independent election commission and security forces ensure that all parties can campaign freely without fear, the election may be severely compromised," Ali Dayan Hasan, the head of Human Rights Watch in Pakistan, said in a statement issued Monday.